w1: new w1_ds2406 driver

Some preliminary work at making use of this driver led me to implement
CRC-16 checks on read and write to deal with the occasional glitchiness of
the 1-Wire bus.  The revised driver (attached) returns an I/O error if the
CRC check fails.  When reading the chip's state, either you get a valid
indication or you get an I/O error.  When changing its state, either the
change is successful or an I/O error is returned.

Signed-off-by: Scott Alfter <scott@alfter.us>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/w1/w1_family.h b/drivers/w1/w1_family.h
index 26ca134..0d18365 100644
--- a/drivers/w1/w1_family.h
+++ b/drivers/w1/w1_family.h
@@ -40,6 +40,7 @@
 #define W1_FAMILY_DS2760	0x30
 #define W1_FAMILY_DS2780	0x32
 #define W1_FAMILY_DS2413	0x3A
+#define W1_FAMILY_DS2406	0x12
 #define W1_THERM_DS1825		0x3B
 #define W1_FAMILY_DS2781	0x3D
 #define W1_THERM_DS28EA00	0x42